Cushioned gas-operated well apparatus



y 7, 1953 ac. BAKER 2,644,529

CUSHIONED GAS-OPERATED WELL APPARATUS l atentecl July 7, 1953 CUSHIONED GAS-OPERATED WELL APPARATUS Reuben C. Baker, Coalinga, Calif., assignor to Baker Oil Tools, Inc., Vernon, Calif., a corporation of California Application September 20, 1948, Serial No. 50,193

6 Claims. (01. 166 -13) The present invention relates to well .devices, and more particularly to sub-surface devices or apparatus employed in bore holes, such as oil, gas and similar wells.

Certain types of sub-surface Well apparatus are operated by gas pressure. Compressed air, hydrogen, acetylene, products of combustion, and the like may constitute the motivating gaseous force. The compressed gas may not only operate the well apparatus, but may also eiiect release ofv the apparatus, or part of it, from the well bore, to enable its withdrawal to the top of the well.

Heretofore, release of all, or a portion, of the apparatus has permitted the gas, which might be under comparatively high pressure, to expand suddenly, imposing severe shock loads on the equipment, and, at times,.inflicting damage on some of its parts.

Accordingly, an object of the present invention is to prevent damage to fluid or gasoperated sub-surface apparatus upon release of the load. upon the apparatus.

Another object of the invention is to cushion the shock incident to sudden release of the load on sub-surface gas operated apparatus.

' A further object of the invention is to prevent sudden expansion of the gas which operates subsurface apparatus, upon release of a large portion of the load on the apparatus.

Still another object of the invention is to prevent expansion of the gas which operates subsurface apparatus to a comparatively small additional extent, upon release of a substantial portion of the load upon the apparatus.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the in vention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referringv to the drawings:

Figures 1a and lb together constitute a longitudinal section through a well apparatus positioned in a Well casing, with the parts occupying their initial position for lowering the apparatus through the casing, Fig. 1b forming a lower continuation of Fig. 1a.

Figs. 2a and 2b are views similar to Figs. la

and 1b of the apparatus, with part of the apparatus secured in awell casing, and another part released from the first part for withdrawal from the well casing; and

Fig. 3 is a cross-section taken along the line 33 on Fig. 1a.

'In the form of the invention disclosed in the drawings, it is desired to run a Well packer. A

to a desired location in a well casing B dis-' posed'within a bore hole. The packer is then anchored in packed-off condition against the wen casing through use of a setting tool ,C connected to it. This setting tool 'is attached to the lower end of a running-in string, such as a wire line D extending to the top of the Well bore.

The well packer A may assume any desired form. The one disclosed in the drawings includes a tubular main body 10 whose central passage ll may be closed by a plug l2. A guide it is rection for slidable engagement with a corre-' sponding, or externally tapered, surface ll on a frusto-conical expander I8 slidable on the body. This expander is connected to the lower end of a packing sleeve l9, of rubber or similar material, disposed around-the body iii, the upper end of this packing sleeve being connected to an upper expander 20 having an upwardly and inwardly inclined externally tapering surface 2! engageable with corresponding tapered surfaces 22 on a plurality of upper segmental slips 23.

Initially, the slips I4, 23 and packing element l9 are retained in retracted positions with respect to the packing body 10. Shear screws 25, 25, or other suitable frangible connecting elements, secure the upper and lower conicalexpanders 2i],

[8 to the body, with the intervening packing sleeve [9 held in retracted position. The upper and lower slips 23, 14 are also held in retracted posi-' tions by shear screws 26, 21, attaching them to their associated upper and lower expanders 20, I8.

The shear'screws 26 attaching the upperslipsv 23 to the upper expander 20 have a combined shearing strength which is substantially less than the shear value of the screws 24 holding the upper 3. expander to the body I0. These latter screws have a lesser shear value than the screws 25, 21 securing the lower expander l8 to the body, and the lower slips l4 to the lower expander. These relative shear values are selected to secure detachment, at first, of the upper slips 23 from the upper expander 20, and the movement of the upper slips downwardly along the upper expander and radially outward into anchoring engagement with the casing wall. A subsequent upward strain or pull on the packer body l then shears the screws 24 holding the upper expander 20 to the body I0, and moves the lower expander 18 and slips [4 with the body toward the upper expander 20 and slips 23, in order to effect compression of the packing [9 between the expanders and its outward expansion into firm-sealing engagement with the wall of the casing.

Thereafter, an increasesin the upward' pull'or force on the packer body ID substantially simultaneously shears the screws 25, 21 holding the lower expander I8 to the body, and the lower slips"! 4 to the lower expander, to cause the lower flange I and guide I3 on the body' to shift the lower slips l4 upwardly along the'lower expander and radially outward into anchoring engagement with the wall of the casing B. A split retractor ring 28 maybe disposed in the expander for engagement with one of several buttress thread ratchet teeth 29 formed on the exterior of the body IE, to lock the latter against downward movement (see Fig. 2b).

In the form of inventiondisclosed in thedraw ings, setting of the well packer A is dependent upon the development of a gas pressure within a setting tool Cinitially secured to the well packer. inder 30, consisting of a general cylindrical sleeve 3|, an upper head 32"threadedinto the sleeve, and also a lower head 33 threaded into the sleeve. Leakage from the cylinder through the threaded-connections may be prevented by' suitable side seals 34, 35 in peripheral grooves 36, STjin'the heads engaging the inner wall of the cylinder sleeve 3 I.

A piston 40 is slidably mountedin the cylinder 30. This piston has one or more ring'gro'oves 4| .in its periphery for the accommodation of seal rings 42 to prevent leakage between the. piston and cylinder. may consist of rubber, round in cross-section, to guard against leakage in both'directi'ons, The

upper. end of a piston, ro'd'43 is threadedl'y' con-.'

nected to the piston, the rod extending downwardly through the lower cylind'erihead33to a point the'rebelow, where an anvil or cross-piece 44 is mounted within a transverse slot45'in the rod. Leakage between the rod 43' and lower cylinder head 33 is prevented by suitable rod pack ing in the form of one or more round rubber, or rubber-like, seals 46, engaging the periphery of the rod, and disposed "within suitable ring grooves 41 in the head 33. The packing rings 46 prevent leakage of liquids from the well easing into the cylinder 30' below the piston 40, insuring that air'under atmospheric pressure is present below the piston when the apparatus is assembled. and lowered in the well casing. 7

It is desired to transfer the downwardfmovement or force of the piston '40 and the piston rod1 43 to the upper slips 23 of the packer, and the rel ative upward movement ofthe cylinder 30 to thepacker 'body I 0, in order to obtain the desired. anchoring of thepa'ck'er in the wen casing. To accomplish this purpose, a "tubular' actuating This gas pressure is' developedwithinia cyl-' IAs disclosed, these rings'42 mandrel 48 is threadedly connected to the lower end of the lower cylinder head 33. The lower end 56 of the mandrel is secured to'a sleeve 49, threaded into the upper end of the body I0, through the agency of a frangible connecting pin 5!. As specifically disclosedthe lower end of the mandrel is of reduced diameter and is piloted within the sleeve 49, the pin extending transversely through the sleeve 49 and piloted mandrel portion 50.

'The" piston rod 43 is movable downwardly within the bore 52 of the actuatin mandrel 48, the cross-piece 44 projecting in opposite directions from the rod through diametrically opposed, longitudinally extending slots 53 formed through the mandrel wall. The cross-piece also extends into opposed slots 58; formed through a setting ring or sleeve 56 slidably mounted on the actuating mandrel 43, to form a connection between the piston rod 43 and the setting ring 56. A setting sleeve or skirt 51' is adjustably threaded on the setting ring, its lower end 59 engaging the tops of the upper slips 23.

A fluid or gaseous force is developed within the cylinder 36' above-the piston-40; This force moves the piston and piston rod 43 downwardly, and the cylinder 36' in a' relative upward 'direction. The downward movement of the rod 43- is transmitted to the setting sleeve or skirt 51' through the anvil 44 and'settingsleeve 56; whereas, the upward movement' of the cylinder30. is" transmitted to the packer body) through the actuating mandrel 48, frangible pin 5|, and the sleeve 49. Accordingly, it is apparent that the development of sufiicientpressure in the-cylin der 30 will eventually shearthescrews26. hold ing the upper slips 23 to the'-expander 20;'and

move the slips outwardly'against" thecasing B. Thereafter, the cylinder, Silwill move upwardly,

to pull the body Win the same direction, forthe purpose of expanding the packing sleeve '19 against the'casing B, and then the lower slips 14 against the casing, in the "manner described above.

In order to obtain the desired operationalsequence, a combustible fuel 69 maybecontained within the upper end'of the cylinder 30;, The

combustion charge, such as a railway flaret of cylindrical or stick form, is placedj'in' the head end 32 of thecylinder within a combustion chamber 10 formed therein. This'combustion charge is ignited by a blank cartridge 'H" contained withma gun barrelplz inserted within theupperend. of the cylinder head 32. Leakagebetween the barrel and head is' prevented by a suitable; side seal 13 on the barrel engaging the Wall ofthe head.

The barrel 12 is, threaded into a firing head'li4, which, in turn, is threadedly secured to the upper end of the cylinder head 32. The wire linei run.- ning-in string D is suitably securedLto the firing, head 74', in a. known manner, and hasithe lower end of its electrically conductive. wire or'co're 15 connected electrically to a'. heating. filament" 16 contained within the cartridge I I The apparatus is lowered in the. well borewithj the parts disposed in the position shown in Figs. 1a and 1b. When the point in the. casingis reached at which the wellfpackerA is? to be s'et,

the circuit through the cartridge filament T6. is completed, which firesthe cartridge TI". The, flame issuing therefrom-ignites the upper endof the combustible charge 59;initia'ting its combustion. The chargeburns andidevelopsagaseous pressure withinthe" cylinder '30. Asthe pressure 5 increases, the piston M is urged downwardly and the cylinder at relatively upwardly. The force of the piston M1 is transmitted through the rod 43, cross-piece 44 and setting ring 56 to the sleeve 5?, which bears against the upper slips 23. When sufficient pressure has been developed within the cylinder to overcome the shear strength of the screws 25, and also the hydrostatic head of fluid acting upwardly on the piston rod 43, the slips 23 are released from the expander 25) and are pushed downwardly along the latter into outward engagement with the casing B.

As the combustible charge continues to burn, the gas pressure within cylinder 30 increases to a further extent. Since the upper slips. 23 are wedged against the casing B, the piston 40 cannot move downwardly to any further appreciable extent. Instead, the cylinder 36, actuating mandrel 48, sleeve 49, and packer body I are urged in an upward direction. When the pressure and force within the cylinder has increased sufiiciently to overcome the shear strength ofthe screws 24 holding the upper expander 2B-to the body, such screws are disrupted and the packer'body i0 is moved upwardly within the upper expander 23 to compress the packer sleeve I9 between the upper and lower expanders 29, I8, forcing it into firm sealing engagement with the casing wall.

If the cylinder gas pressure increases further, as a result of the continued combustion of the charge 69, the screws 25, 21, attaching the lower expander 18 to the body in and the lower slips M to the lower expander, are disrupted, allowing the cylinder 38 to move upwardly and carry the body l and lower slips I l in an upward direction, to shift the v latter radially outward into engagement with the casing B.

The pressure in the cylinder continues to increase as combustion of the charge 69 proceeds, and all of the packer elements are engaged more firmly with the casing B. When the pressure exceeds the shear strength of the pin 5|, securing the lower .end 58 of the actuating mandrel as to the sleeve :39, this pin is sheared to release automatically the setting tool C from the well packer A. All of the mechanism, with the exception of the packer A, may now be removed from the well casing B.

At the time that the connector pin 5! is sheared to release the setting tool C from the well packer A, the piston has not been moved downwardly to its fullest extent within the cylinder 30. Shearing of the pin 5| releases the load on the cylinder at and piston 49, and ordinarily allows the gas in the cylinder to partake of a sudden expansion, which shifts the piston All relatively downwardly to the extent limited by its engagement with the lower cylinder head 33.

When it is realized that comparatively high pressures, of the order of 5000 p. s. i. and higher, may be developed in the cylinder 33, in order to disrupt the connector pin 5|, it is evident that a tremendous blow would be struck by the piston 40 upon the cylinder head 33. The reaction of this blow and the sudden movement of the cylinder 30 and piston 49 introduce a recoil or shock load on all of the equipment in the well bore, which sometimes results in damage to some of the parts.

By virtue of the present invention, the above disadvantages are overcome in a comparatively simpler manner. A spring-like cushioning element, in the form of a rubber sleeve 23, is placed in the cylinder 30 below the piston 49 and around the piston rod 43. This rubber sleeve may have 6" aninitial clearance with the wall of'the'cylinder. It rests upon the lower cylinder head 33, with its upper end spaced a substantial distance below the piston 40.

The dimensions of the rubber cushioning sleeve are so proportioned as to allow relative down-. ward movement of the piston 4c in the cylinder 3! in the manner described above, to achieve full setting of the well packer A and the disruption of I the connector pin 5| without substantial interference from the cushioning sleeve 88. upon ignition of the combustible fuel 59, the piston 40 maymove downwardly to expand the upper slips 23 against the casing B, upward move-' pin 5| allows the piston 4i! to move relatively downwardly within the cylinder 30 to only a small additional extent, since only a slight additional movement is necessary to fully expand the cushioning sleeve 80 against the piston rod 43 and cylinder sleeve 3 l and completely fill the annular space defined between the sleeve '3! and rod 43, and between the lower cylinder head 33 and piston 38. The piston 46 cannot move downwardlyto any further extent, since such movement is precluded by the fully compressed rubber cushioning sleeve ac. As is well known, rubber, when fully confined, functions in the same manner as water, and is incompressible (see Fig. 2a).

Accordingly, following disruption of the connector'pin- 5!, the compressed gases Within the cylinder 3!! are prevented from expandingv suddenly to. a large extent, since the piston id) can only move downwardly to a slightly further extent,

and this downward movement is retarded to some degree by the necessity to fully compress the rubber cushioning sleeve 80 within the annular space between the piston rod 43 and sleeve 3!. As a result, shock loads are prevented from being imposed upon the setting tool mechanism C, and there are no'reactive jolts or force imparted to the equipment. The connector pin 55 is disrupted without introducing violence into the action of the apparatus, which can then be withdrawn to the top of the well bore.

It is, therefore, apparent that apparatus has been provided for preventing damage to the equipment, which cushions the shock incident to sudden release of the load on the apparatus, and which prevents sudden expansion of the generated gases, by limiting the extent to which such gases can move the parts of the apparatus following release of the load on the apparatus.

The inventor claims:

1. In well apparatus: a well device adapted to be operated in a well bore; fluid actuated means operatively connected to said well device, comprising a closed cylinder and piston mean slidable in said cylinder; means sealing a crosssectional area of said cylinder to provide a completely enclosed space in said cylinder on the low pressure side of said piston means and to prevent the well fluid externally of said cylinder from entering said enclosed space during lowering of the apparatus in the well bore; and cushioning means in said enclosed, space disposed 1 Thus,

7 initially in spaced relation to said piston means andengagedby said piston means, afterat least partial actuationof said well deviceby said fluid actuated means, to retard the continuing relative moyementof said piston means in, said cylinder.

2. In well apparatus: a well device adapted-to be operated in a Well'bore; fluid actuated means for-operating said well device, comprising-acylinder and a piston slidablein said cylinder; means sealing a cross-sectional area of said cylinder to provide a completely enclosed space in said cylinderonthe low pressure side of said piston and to prevent the Well fluid: externally of said cylinder from entering said enclosed space during loweringof the apparatus in the Well bore; means releasable by said fluid actuated means releasably securing said fluid actuated means to said Well device; andcushioning means in said enclosed space belowsaid piston and engageable with said piston;. after at least partial actuation of said well device bysaid fluid actuated means, to retard continuing relative movement. of said piston in said cylinder to its final position of rest in said cylinder after release of said securing means.

3. In well apparatus: a well device having a body and slips disposed around said body and engageable with a well casing; fluid actuated means cooperable with said body and engageable with said slips to expand said slips against the casing, said fluid actuated means comprising a closed cylinder and piston slidable in said cylinder; means sealing a cross-sectional area of said cylinder to provide a completely enclosed space in said cylinder on the low pressure side of said piston and to prevent the well fluid externally of said cylinder from entering said enclosed space during lowering of the apparatus in the well bore means releasable by said fluid actuated means releasably securing said fluid actuated means to said body; and cushioning means in said enclosed space engageable by said piston, after at least partial actuation of said Well device by said fluid actuated means, to retard the continuing relative movement of said piston in said cylinder after release of said releasable means.

4. Inwell apparatus: a well device adapted to be operated in a well bore; fluid actuated means for operating said well device, comprising a cylinder and a piston slidable in said cylinder; means sealing a cross-sectional area of said cylinder to provide a completely enclosed space in said cylinder on the low pressure side of said piston and to prevent the Well fluid externally of said cylinder from enterin said enclosed space during lowering of the apparatus in the Well bore; means releasable by said fluid actuated means releasably securing said fluid actuated means to said Well device; and cushioning means in said enclosed space disposed initially in spaced relation to said piston and engaged by said piston after at least 8 partial actuation of; saidwell device by-said fluid actuated 'means' to retard the continuing relative movement of said; piston in said cylinder after release of; said releasable means.

5. In well apparatusz-a well device having a body and normally retracted means for engagementg-with a well casing; fluid actuated means for: setting said" device in said Well casing comprisin a piston for exerting a downward force 0n:v said normally-retracted. means and a closed cylinder for exerting an' upward force on said body; means sealing a cross-sectional area of said cylinder to providea completely enclosed space in said cylinder on the low pressure side of said: piston and to prevent the well fluid externallyof said cylinder from. entering said enclosed space durin lowering: ofthe; apparatus inthe wellbore; readily disruptablemeans in series with said cylinder and body fortransmitting said upward" force between said cylinder-and body; and a pliant, elastic material in saidenclosed space below said piston and disposed initially in-spacedrelation with respect thereto, said piston engaging said material after at-leastpartial actuation of said well device by said fluid actuated means to retard the continuingrelative movement of said; piston-in said cylinder after breaking of said readily disruptable-means.

6. In well apparatus: a well device adapted to be operated in-a well bore; fluid actuated means for operatingsaid well device, comprising a cylinderand-a piston slidable in said'cylinder; means sealing a cross-sectional area ofsaid cylinder to provide a completely enclosed spacein saidcylin-,

References Cited; in the flleof this patent UNITED. STATES'PATEN'IS Number Name Date 1,029,462 Rife -s. June. 11, 1912 2,076,307 Wells et a1. Apr.l6, 1937 2,189,937 Broyles Feb. 13, 1940 2,210,020 Anderson Aug. 6,1940 2,323,321 Futlal July 6, 1943 2,373,006 Baker Apr. 3, 1945 2,440,150 Mitchell Apr. 20, 1948. 

